Replace more ObserverList with base::ObserverList.

components/proximity_auth/cryptauth/mock_cryptauth_client.h

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef COMPONENTS_PROXIMITY_AUTH_MOCK_CRYPTAUTH_CLIENT_H
 #define COMPONENTS_PROXIMITY_AUTH_MOCK_CRYPTAUTH_CLIENT_H
 
 #include "base/macros.h"
 #include "base/observer_list.h"
 #include "components/proximity_auth/cryptauth/cryptauth_client.h"
@@ skipping 55 matching lines @@
   scoped_ptr<CryptAuthClient> CreateInstance() override;
 
   void AddObserver(Observer* observer);
   void RemoveObserver(Observer* observer);
 
  private:
   // Whether to create StrictMocks or NiceMocks.
   bool is_strict_;
 
   // Observers of the factory.
-  ObserverList<Observer> observer_list_;
+  base::ObserverList<Observer> observer_list_;
 
   DISALLOW_COPY_AND_ASSIGN(MockCryptAuthClientFactory);
 };
 
 }  // namespace proximity_auth
 
 #endif  // COMPONENTS_PROXIMITY_AUTH_MOCK_CRYPTAUTH_CLIENT_H